In ten minutes a heart can beat 700 times. At this rate in how many minutes will a heart beat 140 times

You can do this with ratio method

10 mins : 700 times

x : 140 times

cross multiply and then solve it algebraically

such as 10 * 140 = 700x

10*140/700 = x

2 = x

in 2 minutes the heart beat 140 times.

A heart will beat 140 times in two minutes